<template>
	<view>
		<cu-custom bgColor="bg-blue" :isBack="true">
			<block slot="backText">返回</block>
			<block slot="content">签字</block>
		</cu-custom>
		
			<view class="contentContainer bg-top bg-blue">
				<view class="contentHeader boxWatch">
					<text class="signKey">签字人员</text>
					<text>{{signName}}</text>
				</view>
				
				<view class="bodyBox">
					<view class="contentName boxWatch">
						<view>
							<view class="titleLine"><text class="signKey">补充说明/备注/措施</text></view>
							<view class="textCon">
								<u-input
									type="textarea"
									v-model="textAreaVal"
									:border="false"
									height="300"
									:clearable="false"
									:auto-height="false"
									:maxlength="textAreaMaxLength"
								/>
								<view class="wordsTip">
									已输入:{{textAreaVal.length}}/{{textAreaMaxLength}}
								</view>
							</view>
						</view>
					</view>
					
					<view class="contentName boxWatch">
						<view>
							<view class="titleLine"><text class="signKey">签字</text></view>
							
							<!-- <sign></sign> -->
							<view class="wrapper">
								<view class="handRight">
									<view class="handTitle">请签名</view>
								</view>
								
								<view class="handCenter">
									<canvas class="handWriting" :disable-scroll="true" @touchstart="uploadScaleStart" @touchmove="uploadScaleMove"
									 @touchend="uploadScaleEnd" canvas-id="handWriting"></canvas>
								</view>
								<view class="handBtn">
									<!-- <image @click="selectColorEvent('black','#1A1A1A')" :src="selectColor === 'black' ? '../static/other/color_black_selected.png' : '../static/other/color_black.png'"
									 :class="[selectColor === 'black' ? 'color_select' : '', 'black-select']"></image>
									<image @click="selectColorEvent('red','#ca262a')" :src="selectColor === 'red' ? '../static/other/color_red_selected.png' : '../static/other/color_red.png'"
									 :class="[selectColor === 'red' ? 'color_select' : '', 'black-select']"></image> -->
									<button @click="retDraw" class="delBtn">重写</button>
									<button @click="saveCanvasAsImg" class="saveBtn">保存</button>
									<button @click="previewCanvasImg" class="previewBtn">预览</button>
									<button @click="uploadCanvasImg" class="uploadBtn">上传</button>
									<button @click="subCanvas" class="subBtn">完成</button>
								</view>
								
							</view>
							
						</view>
					</view>
					
					<u-button type="primary" @click="submit">提交</u-button>
				</view>
			</view>

		
	</view>
	
</template>

<script>
	import sign from '../../tn_components/sign.vue';
	export default {
		components: {
			sign
		},
		data() {
			return {
				signName:'',
				textAreaVal:'',
				textAreaMaxLength: 300,
				canvasName: 'handWriting',
				ctx: '',
				canvasWidth: 0,
				canvasHeight: 0,
				transparent: 1, // 透明度
				selectColor: 'black',
				lineColor: '#1A1A1A', // 颜色
				lineSize: 1.5, // 笔记倍数
				lineMin: 0.5, // 最小笔画半径
				lineMax: 4, // 最大笔画半径
				pressure: 1, // 默认压力
				smoothness: 60, //顺滑度，用60的距离来计算速度
				currentPoint: {},
				currentLine: [], // 当前线条
				firstTouch: true, // 第一次触发
				radius: 1, //画圆的半径
				cutArea: {
					top: 0,
					right: 0,
					bottom: 0,
					left: 0
				}, //裁剪区域
				bethelPoint: [], //保存所有线条 生成的贝塞尔点；
				lastPoint: 0,
				chirography: [], //笔迹
				currentChirography: {}, //当前笔迹
				linePrack: [] //划线轨迹 , 生成线条的实际点
			}
		},
		
		onLoad(option) {
			this.signName = option.name
			let canvasName = this.canvasName;
			let ctx = wx.createCanvasContext(canvasName);
		
			this.ctx = ctx;
			var query = wx.createSelectorQuery();
			query
				.select('.handCenter')
				.boundingClientRect(rect => {
					this.canvasWidth = rect.width;
					this.canvasHeight = rect.height;
		
					/* 将canvas背景设置为 白底，不设置  导出的canvas的背景为透明 */
					this.setCanvasBg('#fff');
				})
				.exec();
		},

		methods: {

			submit() {
				this.textAreaVal = '';
				uni.navigateBack();
			},
				// 笔迹开始
				uploadScaleStart(e) {
					if (e.type != 'touchstart') return false;
					let ctx = this.ctx;
					ctx.setFillStyle(this.lineColor); // 初始线条设置颜色
					ctx.setGlobalAlpha(this.transparent); // 设置半透明
					let currentPoint = {
						x: e.touches[0].x,
						y: e.touches[0].y
					};
					let currentLine = this.currentLine;
					currentLine.unshift({
						time: new Date().getTime(),
						dis: 0,
						x: currentPoint.x,
						y: currentPoint.y
					});
					this.currentPoint = currentPoint;
					// currentLine
					if (this.firstTouch) {
						this.cutArea = {
							top: currentPoint.y,
							right: currentPoint.x,
							bottom: currentPoint.y,
							left: currentPoint.x
						};
						this.firstTouch = false;
					}
					this.pointToLine(currentLine);
				},
				// 笔迹移动
				uploadScaleMove(e) {
					if (e.type != 'touchmove') return false;
					if (e.cancelable) {
						// 判断默认行为是否已经被禁用
						if (!e.defaultPrevented) {
							e.preventDefault();
						}
					}
					let point = {
						x: e.touches[0].x,
						y: e.touches[0].y
					};
		
					//测试裁剪
					if (point.y < this.cutArea.top) {
						this.cutArea.top = point.y;
					}
					if (point.y < 0) this.cutArea.top = 0;
		
					if (point.x > this.cutArea.right) {
						this.cutArea.right = point.x;
					}
					if (this.canvasWidth - point.x <= 0) {
						this.cutArea.right = this.canvasWidth;
					}
					if (point.y > this.cutArea.bottom) {
						this.cutArea.bottom = point.y;
					}
					if (this.canvasHeight - point.y <= 0) {
						this.cutArea.bottom = this.canvasHeight;
					}
					if (point.x < this.cutArea.left) {
						this.cutArea.left = point.x;
					}
					if (point.x < 0) this.cutArea.left = 0;
		
					this.lastPoint = this.currentPoint;
					this.currentPoint = point;
		
					let currentLine = this.currentLine;
					currentLine.unshift({
						time: new Date().getTime(),
						dis: this.distance(this.currentPoint, this.lastPoint),
						x: point.x,
						y: point.y
					});
		
					this.pointToLine(currentLine);
				},
				// 笔迹结束
				uploadScaleEnd(e) {
					if (e.type != 'touchend') return 0;
					let point = {
						x: e.changedTouches[0].x,
						y: e.changedTouches[0].y
					};
					this.lastPoint = this.currentPoint;
					this.currentPoint = point;
		
					let currentLine = this.currentLine;
					currentLine.unshift({
						time: new Date().getTime(),
						dis: this.distance(this.currentPoint, this.lastPoint),
						x: point.x,
						y: point.y
					});
		
					if (currentLine.length > 2) {
						var info = (currentLine[0].time - currentLine[currentLine.length - 1].time) / currentLine.length;
						//$("#info").text(info.toFixed(2));
					}
					//一笔结束，保存笔迹的坐标点，清空，当前笔迹
					//增加判断是否在手写区域；
					this.pointToLine(currentLine);
					var currentChirography = {
						lineSize: this.lineSize,
						lineColor: this.lineColor
					};
					var chirography = this.chirography;
					chirography.unshift(currentChirography);
					this.chirography = chirography;
		
					var linePrack = this.linePrack;
					linePrack.unshift(this.currentLine);
					this.linePrack = linePrack;
					this.currentLine = [];
				},
				retDraw() {
					this.ctx.clearRect(0, 0, 700, 730);
					this.ctx.draw();
		
					//设置canvas背景
					this.setCanvasBg('#fff');
				},
				//画两点之间的线条；参数为:line，会绘制最近的开始的两个点；
				pointToLine(line) {
					this.calcBethelLine(line);
					return;
				},
				//计算插值的方式；
				calcBethelLine(line) {
					if (line.length <= 1) {
						line[0].r = this.radius;
						return;
					}
					let x0,
						x1,
						x2,
						y0,
						y1,
						y2,
						r0,
						r1,
						r2,
						len,
						lastRadius,
						dis = 0,
						time = 0,
						curveValue = 0.5;
					if (line.length <= 2) {
						x0 = line[1].x;
						y0 = line[1].y;
						x2 = line[1].x + (line[0].x - line[1].x) * curveValue;
						y2 = line[1].y + (line[0].y - line[1].y) * curveValue;
						//x2 = line[1].x;
						//y2 = line[1].y;
						x1 = x0 + (x2 - x0) * curveValue;
						y1 = y0 + (y2 - y0) * curveValue;
					} else {
						x0 = line[2].x + (line[1].x - line[2].x) * curveValue;
						y0 = line[2].y + (line[1].y - line[2].y) * curveValue;
						x1 = line[1].x;
						y1 = line[1].y;
						x2 = x1 + (line[0].x - x1) * curveValue;
						y2 = y1 + (line[0].y - y1) * curveValue;
					}
					//从计算公式看，三个点分别是(x0,y0),(x1,y1),(x2,y2) ；(x1,y1)这个是控制点，控制点不会落在曲线上；实际上，这个点还会手写获取的实际点，却落在曲线上
					len = this.distance({
						x: x2,
						y: y2
					}, {
						x: x0,
						y: y0
					});
					lastRadius = this.radius;
					for (let n = 0; n < line.length - 1; n++) {
						dis += line[n].dis;
						time += line[n].time - line[n + 1].time;
						if (dis > this.smoothness) break;
					}
		
					this.radius = Math.min((time / len) * this.pressure + this.lineMin, this.lineMax) * this.lineSize;
					line[0].r = this.radius;
					//计算笔迹半径；
					if (line.length <= 2) {
						r0 = (lastRadius + this.radius) / 2;
						r1 = r0;
						r2 = r1;
						//return;
					} else {
						r0 = (line[2].r + line[1].r) / 2;
						r1 = line[1].r;
						r2 = (line[1].r + line[0].r) / 2;
					}
					let n = 5;
					let point = [];
					for (let i = 0; i < n; i++) {
						let t = i / (n - 1);
						let x = (1 - t) * (1 - t) * x0 + 2 * t * (1 - t) * x1 + t * t * x2;
						let y = (1 - t) * (1 - t) * y0 + 2 * t * (1 - t) * y1 + t * t * y2;
						let r = lastRadius + ((this.radius - lastRadius) / n) * i;
						point.push({
							x: x,
							y: y,
							r: r
						});
						if (point.length == 3) {
							let a = this.ctaCalc(point[0].x, point[0].y, point[0].r, point[1].x, point[1].y, point[1].r, point[2].x, point[2]
								.y, point[2].r);
							a[0].color = this.lineColor;
							// let bethelPoint = this.bethelPoint;
							// bethelPoint = bethelPoint.push(a);
							this.bethelDraw(a, 1);
							point = [{
								x: x,
								y: y,
								r: r
							}];
						}
					}
					this.currentLine = line;
				},
				//求两点之间距离
				distance(a, b) {
					let x = b.x - a.x;
					let y = b.y - a.y;
					return Math.sqrt(x * x + y * y);
				},
				ctaCalc(x0, y0, r0, x1, y1, r1, x2, y2, r2) {
					let a = [],
						vx01,
						vy01,
						norm,
						n_x0,
						n_y0,
						vx21,
						vy21,
						n_x2,
						n_y2;
					vx01 = x1 - x0;
					vy01 = y1 - y0;
					norm = Math.sqrt(vx01 * vx01 + vy01 * vy01 + 0.0001) * 2;
					vx01 = (vx01 / norm) * r0;
					vy01 = (vy01 / norm) * r0;
					n_x0 = vy01;
					n_y0 = -vx01;
					vx21 = x1 - x2;
					vy21 = y1 - y2;
					norm = Math.sqrt(vx21 * vx21 + vy21 * vy21 + 0.0001) * 2;
					vx21 = (vx21 / norm) * r2;
					vy21 = (vy21 / norm) * r2;
					n_x2 = -vy21;
					n_y2 = vx21;
					a.push({
						mx: x0 + n_x0,
						my: y0 + n_y0,
						color: '#1A1A1A'
					});
					a.push({
						c1x: x1 + n_x0,
						c1y: y1 + n_y0,
						c2x: x1 + n_x2,
						c2y: y1 + n_y2,
						ex: x2 + n_x2,
						ey: y2 + n_y2
					});
					a.push({
						c1x: x2 + n_x2 - vx21,
						c1y: y2 + n_y2 - vy21,
						c2x: x2 - n_x2 - vx21,
						c2y: y2 - n_y2 - vy21,
						ex: x2 - n_x2,
						ey: y2 - n_y2
					});
					a.push({
						c1x: x1 - n_x2,
						c1y: y1 - n_y2,
						c2x: x1 - n_x0,
						c2y: y1 - n_y0,
						ex: x0 - n_x0,
						ey: y0 - n_y0
					});
					a.push({
						c1x: x0 - n_x0 - vx01,
						c1y: y0 - n_y0 - vy01,
						c2x: x0 + n_x0 - vx01,
						c2y: y0 + n_y0 - vy01,
						ex: x0 + n_x0,
						ey: y0 + n_y0
					});
					a[0].mx = a[0].mx.toFixed(1);
					a[0].mx = parseFloat(a[0].mx);
					a[0].my = a[0].my.toFixed(1);
					a[0].my = parseFloat(a[0].my);
					for (let i = 1; i < a.length; i++) {
						a[i].c1x = a[i].c1x.toFixed(1);
						a[i].c1x = parseFloat(a[i].c1x);
						a[i].c1y = a[i].c1y.toFixed(1);
						a[i].c1y = parseFloat(a[i].c1y);
						a[i].c2x = a[i].c2x.toFixed(1);
						a[i].c2x = parseFloat(a[i].c2x);
						a[i].c2y = a[i].c2y.toFixed(1);
						a[i].c2y = parseFloat(a[i].c2y);
						a[i].ex = a[i].ex.toFixed(1);
						a[i].ex = parseFloat(a[i].ex);
						a[i].ey = a[i].ey.toFixed(1);
						a[i].ey = parseFloat(a[i].ey);
					}
					return a;
				},
				bethelDraw(point, is_fill, color) {
					let ctx = this.ctx;
					ctx.beginPath();
					ctx.moveTo(point[0].mx, point[0].my);
					if (undefined != color) {
						ctx.setFillStyle(color);
						ctx.setStrokeStyle(color);
					} else {
						ctx.setFillStyle(point[0].color);
						ctx.setStrokeStyle(point[0].color);
					}
					for (let i = 1; i < point.length; i++) {
						ctx.bezierCurveTo(point[i].c1x, point[i].c1y, point[i].c2x, point[i].c2y, point[i].ex, point[i].ey);
					}
					ctx.stroke();
					if (undefined != is_fill) {
						ctx.fill(); //填充图形 ( 后绘制的图形会覆盖前面的图形, 绘制时注意先后顺序 )
					}
					ctx.draw(true);
				},
				selectColorEvent(str, color) {
					this.selectColor = str;
					this.lineColor = color;
				},
				//将Canvas内容转成 临时图片 --> cb 为回调函数 形参 tempImgPath 为 生成的图片临时路径
				canvasToImg(cb) {
					//这种写法移动端 出不来
		
					this.ctx.draw(true, () => {
						wx.canvasToTempFilePath({
							canvasId: 'handWriting',
							fileType: 'png',
							quality: 1, //图片质量
							success(res) {
								// console.log(res.tempFilePath, 'canvas生成图片地址');
		
								wx.showToast({
									title: '执行了吗？'
								});
		
								cb(res.tempFilePath);
							}
						});
					});
				},
				//完成
				subCanvas() {
					this.ctx.draw(true, () => {
						wx.canvasToTempFilePath({
							canvasId: 'handWriting',
							fileType: 'png',
							quality: 1, //图片质量
							success(res) {
								// console.log(res.tempFilePath, 'canvas生成图片地址');
								wx.showToast({
									title: '以保存'
								});
								//保存到系统相册
								wx.saveImageToPhotosAlbum({
									filePath: res.tempFilePath,
									success(res) {
										wx.showToast({
											title: '已成功保存到相册',
											duration: 2000
										});
									}
								});
							}
						});
					});
				},
				//保存到相册
				saveCanvasAsImg() {
		
					/*
					this.canvasToImg( tempImgPath=>{
						// console.log(tempImgPath, '临时路径');
						wx.saveImageToPhotosAlbum({
							filePath: tempImgPath,
							success(res) {
								wx.showToast({
									title: '已保存到相册',
									duration: 2000
								});
							}
						})
					} );
			*/
		
					wx.canvasToTempFilePath({
						canvasId: 'handWriting',
						fileType: 'png',
						quality: 1, //图片质量
						success(res) {
							// console.log(res.tempFilePath, 'canvas生成图片地址');
							wx.saveImageToPhotosAlbum({
								filePath: res.tempFilePath,
								success(res) {
									wx.showToast({
										title: '已保存到相册',
										duration: 2000
									});
								}
							});
						}
					});
				},
				//预览
				previewCanvasImg() {
					wx.canvasToTempFilePath({
						canvasId: 'handWriting',
						fileType: 'jpg',
						quality: 1, //图片质量
						success(res) {
							// console.log(res.tempFilePath, 'canvas生成图片地址');
		
							wx.previewImage({
								urls: [res.tempFilePath] //预览图片 数组
							});
						}
					});
		
					/*	//移动端出不来  ^~^！！
							this.canvasToImg( tempImgPath=>{
								wx.previewImage({
									urls: [tempImgPath], //预览图片 数组
								})
							} );
					*/
				},
				//上传
				uploadCanvasImg() {
		
					wx.canvasToTempFilePath({
						canvasId: 'handWriting',
						fileType: 'png',
						quality: 1, //图片质量
						success(res) {
							// console.log(res.tempFilePath, 'canvas生成图片地址');
		
							//上传
							wx.uploadFile({
								url: 'https://example.weixin.qq.com/upload', // 仅为示例，非真实的接口地址
								filePath: res.tempFilePath,
								name: 'file_signature',
								formData: {
									user: 'test'
								},
								success(res) {
									const data = res.data;
									// do something
								}
							});
						}
					});
				},
				//设置canvas背景色  不设置  导出的canvas的背景为透明
				//@params：字符串  color
				setCanvasBg(color) {
		
					/* 将canvas背景设置为 白底，不设置  导出的canvas的背景为透明 */
					//rect() 参数说明  矩形路径左上角的横坐标，左上角的纵坐标, 矩形路径的宽度, 矩形路径的高度
					//这里是 canvasHeight - 4 是因为下边盖住边框了，所以手动减了写
					this.ctx.rect(0, 0, this.canvasWidth, this.canvasHeight - 4);
					// ctx.setFillStyle('red')
					this.ctx.setFillStyle(color);
					this.ctx.fill(); //设置填充
					this.ctx.draw(); //开画
				}
			}
		};
</script>

<style lang="scss" scoped>
	.contentContainer {
		color: #000;
		padding: 20rpx 40rpx;
		&.bg-top{
			margin-top: -1rpx;
			width: 750rpx;
			height: 220rpx;
			padding-top: 30rpx;
			border-radius: 0 0 20% 20%;
		}
		.boxWatch{
			padding: 30rpx;
			border-radius: 20rpx;
			background-color: #fff;
			box-shadow: 2px 2px 2px 1px rgba(0, 0, 0, 0.2);
			// width: 90%;
			margin: 0 auto 20rpx;
		}
		.signKey {
			font-weight: 700;
			font-size: 30rpx;
			margin: 10rpx;
		}
		.contentHeader {
			display: flex;
			justify-content: space-between;
			align-items: center;
		}
		
		.bodyBox {
			height: 580%;
			overflow: auto;
		}
		
		.contentName{
			background-color: #fff;
			margin-bottom: 20rpx;
			.titleLine {
				padding: 20rpx 0;
				border-bottom: 1rpx solid rgba(242, 242, 242, 1);
				.signKey {
					font-weight: 700;
					font-size: 30rpx;
					margin: 10rpx;
				}
			}
			.textCon {
				position: relative;
				border: 1rpx solid #ccc;
				padding: 0 0 40rpx 10rpx;
				.wordsTip {
					position: absolute;
					right: 0;
					bottom: 0rpx;
					color: #ccc;
					font-size: 24rpx;
				}
			}
			.wrapper {
				margin: 18rpx 0;
				overflow: hidden;
				display: flex;
				align-content: center;
				flex-direction: column;
				justify-content: center;
				font-size: 28rpx;
			
			
				.handWriting {
					background: #fff;
					width: 100%;
				}
			
				.handRight {
					// display: inline-flex;
					display: none;
					align-items: center;
				}
				
				.handCenter {
					border: 4rpx dashed #e9e9e9;
					flex: 5;
					overflow: hidden;
					box-sizing: border-box;
					margin-bottom: 10rpx;
				}
			
				.handTitle {
					flex: 1;
					color: #666;
					text-align: center
				}
				
				.handBtn button {
					font-size: 28rpx;
				}
				
				.handBtn {
					display: inline-flex;
					flex-direction: row;
					justify-content: space-between;
					align-content: center;
				}
				.subBtn {
					display: inline-flex;
					background: #008ef6;
					color: #fff;
					text-align: center;
					justify-content: center;
				}
				.saveBtn,.delBtn,.previewBtn,.uploadBtn {
					color: #666;
				}
			}
		}
	}
</style>